Quote Originally Posted by Times Roman View Post
ok, turbos may not increase the compression ratio of an engine, but they do stuff more into a cylinder than normally aspirated engines. which is why they often have lower compression ratios and quite often require higher octane gas like premium.

I've been wanting to get another Harley. a bar hopper, with a super charger. only $45k in my estimation. but I have not been riding much lately....
Yup, my 1991 little 3.0 V6 with Twin Turbos (13g) only has 8.5-1 compression and puts out 400hp. I HAVE to run premium in it or it gets detonation/ping and that will destroy an engine eventually and make it run like crap.
My 1967 Camaro had 12.5-1 compression and also had to use premium although it was not the same premium by today's standard, it wouldn't cut the mustard so to speak. I would have to purchase racing fuel to run the car and put lead additive in it.